Frozen embryos generated from surgically retrieved sperm from azoospermic men: are they clinically viable?

To assess the viability of frozen-thawed embryos derived from intracytoplasmic sperm injection (ICSI) in azoospermic men.

Retrospective analysis of 154 consecutive ICSI cycles using surgically retrieved sperm from azoospermic men and case-control comparison of subsequent frozen transfer cycles with those using embryos generated from ejaculated sperm.

Patient and fresh cycle characteristics were similar in both groups. There were no differences between the two groups in the proportion of pronucleate (54% and 62%), and cleavage-stage embryos thawed (46% and 38%), post-thaw survival rates (retrievals: 69%; ejaculated: 73%) or quality of frozen embryos subsequently transferred. Implantation was significantly lower in frozen cycles where embryos were generated from surgically retrieved sperm (0% versus 11.5%; p = 0.03). Both clinical pregnancy rate (5% versus 21%) and live-birth rate (0% versus 21%) were lower in this group, but only the difference in LBR reached borderline statistical difference (p = 0.10).

This small series demonstrates a significant impairment in implantation in FET cycles using embryos generated from surgically retrieved sperm and a trend towards a poorer pregnancy outcome.